Monitoring device including an emitter emitting electromagnetic radiation and a detector positioned to receive the radiation to determine one or more rolling average flow rates

ABSTRACT

A monitoring device provided for monitoring the delivery of fluids through a drip chamber. The device includes an electromagnetic radiation (EMR) source and an EMR detector. The device includes a tubing set mount for receiving a flange or other portion of a tubing set, such that fluid falling through the drip chamber of the tubing set is detected by the detector. The device is operable to determine one or more rolling averages based on intervals of drops or time.

PRIORITY CLAIM

This application is a continuation-in-part of U.S. application Ser. No.16/389,554, filed Apr. 19, 2019, which is a continuation-in-part of U.S.application Ser. No. 15/487,335, filed Apr. 13, 2017, which is acontinuation-in-part of U.S. application Ser. No. 15/362,646, filed Nov.28, 2016, which is a continuation of U.S. application Ser. No.14/923,427, filed Oct. 26, 2015, now U.S. Pat. No. 9,533,095, which is acontinuation of U.S. application Ser. No. 14/188,669, filed Feb. 24,2014, now U.S. Pat. No. 9,199,036, which claims the benefit of U.S.provisional application No. 61/769,109, filed Feb. 25, 2013, and thisapplication further claims the benefit of U.S. provisional applicationNo. 62/323,051 filed Apr. 15, 2016, the contents of each of which areincorporated by reference.

FIELD OF THE INVENTION

The present disclosure relates generally to the delivery of intravenousfluids, more specifically to the monitoring of the delivery of fluidsintravenously to a subject

BACKGROUND OF THE INVENTION

In a variety of settings, it may be useful to ensure precise delivery ofintravenous fluids. One mode of intravenous fluid delivery is thegravity infusion set. One problem with using a gravity infusion set isthe challenge of (a) establishing an accurate initial flow rate and (b)monitoring the flow rate over time.

A device for establishing and monitoring flow rate may be in the form ofan all-in-one device having an infrared light source and photodiode,microprocessor, battery, and display. Such a device may also attachdirectly to the drip chamber and may provide continuous monitoring of aflow rate during a gravity infusion. An infrared light source and aphotodiode may be mounted on opposing sides of the drip chamber so thatthe beam crosses through the path of a falling drip. The microprocessormay periodically measure the light sensed by the photodiode and, bysensing the change in detected light, can detect that a drop has fallen.By measuring the elapsed time between detected drops, the microprocessorcan measure and then display a drop rate.

Two factors which contribute to successful monitoring of a gravityinfusion via optical beam drop detection are (a) proper alignment of asensing element on the drip chamber body and (b) secure attachment of amonitoring device to the drip chamber. If either of these factors arecompromised, incomplete or inaccurate monitoring can result, as the beammay not be properly aligned to sense each falling drop, or the devicemight slip out of alignment. An all-in-one device may be subject to usermisalignment on the drip chamber. In addition, design considerations foran all-in-one device may be complicated by aspects employed to securelyattach the device to a wide variety of user-supplied drip chambers,which may vary significantly in geometry and materials of construction.

SUMMARY OF THE INVENTION

The present disclosure provides devices, methods, and systems forproviding real time monitoring of a fluid flow rate and an accumulatedtotal volume through a drip chamber.

Various embodiments of presently disclosed fluid flow rate monitoringdevices include a source enabled to emit electromagnetic radiation(EMR), a detector enabled to generate a detector signal, a device bodyconfigured and arranged to position the source and the detector about atleast one outer surface of the drip chamber such that the source and thedetector define an optical path across the drip chamber, wherein fluidbetween the source and the detector inhibits EMR travelling along theoptical path; a device body configured and arranged to position thesource and the detector about at least one outer surface of the dripchamber such that the source and the detector define an optical pathacross the drip chamber, wherein fluid between the source and thedetector inhibits EMR travelling along the optical path; and a processordevice that executes instructions that perform actions. The actionsinclude detecting a fluid drop based on at least a difference between aplurality of detector signal values temporally separated by apredetermined lag time and determining the flow rate of fluid based onat least a predetermined drip factor and detecting a plurality of fluiddrops.

In some embodiments, detecting the fluid drop may be further based on acomparison of a plurality of temporally ordered difference values,wherein each of the plurality of difference values correspond todifferences in the plurality of detector signals that are temporallyseparated by the lag time. Additionally, the actions may further includevetoing a detection of a second fluid drop when a temporal differencebetween the detection of the second fluid drop and a detection of afirst fluid drop is less than a predetermined lockout time.

In at least one of the various embodiments, detecting the fluid drop mayfurther include generating a drop waveform based on detector signalvalues sampled at a plurality of temporally ordered times, wherein thedrop waveform is modulated by the fluid drop, generating a lag timedifference waveform based on at least the lag time and a plurality ofdifferences of the drop waveform corresponding to different times, anddetecting the fluid drop based on at least a signal included in the lagtime difference waveform.

In some embodiments, the source may be a light emitting diode (LED). Insome embodiments, the detector may be a photodiode. In at least one ofthe various embodiments, the source may be further enabled to emit EMRwithin a wavelength window, wherein wavelengths within the wavelengthwindow are longer than visible light wavelengths and a sensitivity ofthe detector is greater for at least a portion of the wavelengths withinthe wavelength window than for visible light wavelengths.

In some embodiments, the actions may further include detecting a firstfluid drop at a first detection time, adding the first detection time toa drop history buffer, wherein the drop history buffer includes at leasta plurality of other detection times and each of the other detectiontimes corresponds to a previously detected fluid drop, removing at leastone of the other detection times from the drop history buffer,determining an average drop rate based on at least the detection timesincluded in the history buffer, and determining a drip stability basedon a comparison of a plurality of temporal distances between thedetection times included in the drop history buffer. In someembodiments, the device may include a battery. In some embodiments,power provided to at least one of the detector and the source is pulsed.The provided power may include a bias current. In at least one of thevarious embodiments, bias current provided to the detector and sourcesis pulsed at a predetermined frequency.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred and alternative examples of the present invention aredescribed in detail below with reference to the following drawings.

FIG. 1A shows a flow rate monitoring device adjacent to a gravity fedinfusion set that includes a drip chamber according to embodiments ofthe present disclosure.

FIG. 1B shows a flow rate monitoring device affixed to a drip chamberincluded in a gravity fed infusion set according to embodiments of thepresent disclosure.

FIG. 2 shows a top-down view of a flow rate monitoring device affixed toa drip chamber according to embodiments of the present disclosure.

FIG. 3 shows an exploded view of a flow rate monitoring device with adrip chamber positioned within an optical path between a source anddetector according to embodiments of the present disclosure.

FIG. 4 shows a block level diagram of electronic components included invarious embodiments of a flow rate monitoring device described in thepresent disclosure.

FIGS. 5A and 5B show time series of generated waveforms based on EMRdetection signals as described in the present disclosure.

FIG. 6 shows embodiments of methods for operating a monitoring device.

FIG. 7 shows an embodiment of a clip-style monitoring device bodyaccording to embodiments in the present disclosure.

FIGS. 8A, 8B, and 8C show various views of a monitoring device accordingto embodiments of the present disclosure.

FIG. 9 is an exploded perspective view of a preferred monitoring systemhaving a separate monitoring device and drip chamber with sensorhousing.

FIG. 10 is a front plan view of a drip chamber having an attachedflow-rate sensor housing.

FIG. 11 is a perspective view of a preferred drip chamber and sensorhousing attached to a monitoring device.

FIG. 12 is a schematic view of a preferred drip chamber and sensorhousing having a wired tether and connector configured for attachment toa separate monitoring device.

FIG. 13 is a schematic view of a preferred drip chamber and sensorhousing in wireless communication with one or more separate monitoringdevices.

FIG. 14 is a schematic view of an alternate preferred drip chamber andsensor housing having a wired tether and connector configured forattachment to a separate monitoring device.

FIG. 15 is a schematic view of an alternate preferred drip chamber andsensor housing in wireless communication with one or more separatemonitoring devices.

FIG. 16 is a block diagram of components in a preferred drip chambersensor device body and separate monitoring unit.

FIG. 17 is a schematic view of an alternate preferred drip chamber andsensor housing.

FIG. 18 is a perspective exploded view of a tubing set with dripchamber, shown with a collar for attachment to a monitoring device.

FIG. 19 is a front elevational view of a preferred monitoring device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred monitoring system may consist of a disposable gravity dripset containing drip sensing elements and a mechanical or electricalinterface, and a monitoring unit which interfaces mechanically orelectrically with this drip set. In this system, the monitoring unit mayreceive the sensor values and perform continuous or other monitoring ofthe infusion. This system may at least partially mitigate both thesensor alignment and secure attachment issues that may be seen withall-in-one infusion monitoring devices.

Terms defined herein have meanings as commonly understood by a person ofordinary skill in the areas relevant to the present disclosure. Termssuch as “a,” “an,” and “the” are not intended to refer to only asingular entity, but include the general class of which a specificexample may be used for illustration. The terminology herein is used todescribe specific embodiments of the disclosure, but its usage does notdelimit the disclosure, except as outlined in the claims.

As used herein, the term “electromagnetic radiation” (EMR) is notintended to be limiting. In contrast, as used throughout the presentdisclosure, EMR may refer to any form of energy relating to thepropagation of electromagnetic waves and/or photons. The term EMR is notlimited to a specified range of wavelengths or frequencies within theelectromagnetic spectrum. Rather, EMR, as used herein may include radiowaves, microwaves, infrared (IR) radiation, visible light, ultraviolet(UV) radiation, X-rays, gamma rays, or any other such wavelengths orfrequencies of EMR.

As used herein, the terms “EMR source” and “source” are not intended tobe limiting. In contrast, as used throughout the present disclosure,both “EMR source” and “source” may refer to any device enabled to emitEMR. Non-limiting examples of sources include light emitting diodes(LEDs), lasers, light bulbs, and the like.

As used herein, the terms “EMR detector” and “detector” are not intendedto be limiting. In contrast, as used throughout the present disclosure,both “EMR detector” and “detector” may refer to any device enabled togenerate a signal when in the presence of EMR. In some embodiments, thenature of the signal may be electrical, optical, mechanical, or acombination thereof. A generated electrical signal may be analog ordigital in nature. Some detectors may be referred to as photodetectorsor photosensors. Non-limiting examples of detectors include photodiodes,reverse-biased LEDS, active-pixel sensors (APS), avalanche-photodiode(APD), charge-coupled devices (CCD), photoresistors, photomultipliertubes, photovoltaic cells, and the like.

As used herein, the term “processor device” is not intended to belimiting. Rather, as used throughout the present disclosure, processordevice may refer to one or more devices enabled to execute instructionsthat perform actions. In some embodiments, a processor device mayreceive input and provide corresponding output in response to thereceived input. In some embodiments, processor device may include aprogrammable microcontroller. In some embodiments, a processor devicemay include a microprocessor. A processor device may include a fieldprogrammable gate array (FPGA). In other embodiments, a processor devicemay include an application specific integrated circuit (ASIC). In someembodiments, a processor device may include a computer and/or a mobiledevice. In some embodiments, a processor device may include a processingcore, memory, input/output peripherals, logic gates, Analog-to-DigitalConverters (ADCs) and such. In some embodiments, a processor device mayinclude a plurality of processor devices in communication with oneanother across a network or a bus.

Briefly stated, various embodiments of the devices, methods, and systemsincluded herein are directed towards, but not limited to monitoring theflow rate and total volumetric amount of a fluid, or accumulated fluiddose, delivered to a target through an infusion set, tubing set, orother mechanism. The target may be a medical patient and the fluids maybe delivered intravenously.

A handheld monitoring device may be affixed to a drip chamber includedin the infusion set. By employing an embedded EMR source and an embeddedEMR detector, individual drops falling within the drip chamber may bedetected and counted in real time. Furthermore, the time between eachsuccessive drop may be determined. By monitoring the rate of dropsfalling in the drip chamber and applying an appropriate drip factor, afluid flow rate may be determined. Also, a total volumetric amount, oraccumulated dose, of fluid delivered to the target may be determined.

The determined flow rate and total accumulated fluid dose may beprovided in real time, to a user, through a user interface. The userinterface may include a display unit, input buttons or an alpha-numerickeypad, and an audible speaker. In some embodiments, the user input andoutput functions may be enabled through a touch-sensitive displaydevice.

The user may provide various input information, such as the drip factor,the target fluid flow rate, the target total dose, target flowstability, and the like, through the user interface. The user may alsoprovide corresponding tolerances and/or ranges associated with thesetarget parameters through the user interface.

If the flow becomes unstable, the monitored flow rate falls outside of atolerance range, a total volumetric dose has been achieved or surpassed,or if the flow ceases, the device may provide various alerts to a user.These alerts may include audio alerts provided by the speaker. Thealerts may also include visual alerts provided by the display device. Insome embodiments, at least some of the alerts may be provided in realtime to remote devices, including but not limited to servers/clients,mobile devices, desktop computers, and the like.

Furthermore, the handheld device may be attached or affixed to the dripchamber with a spring-loaded clip. In other embodiments, a trench or achannel included in the monitoring device may enable “snapping” thedevice onto the clip chamber. The device may be battery operated orpower may be supplied through an external source, such as a wall socket.Some embodiments may include a backup battery. In at least one of thevarious embodiments, power may be supplied to a monitoring device byemploying a solar-powered battery.

In some embodiments, the device may be networked to remote devices, suchas a remote computer, a smart phone, or a tablet. Through network means,the device may provide real time information to such remote devices. Aremote user may operate the user interface remotely. In someembodiments, the device may be operated and monitored through anapplication, such as an app running on a mobile device.

Furthermore, the device may be enabled to generate log files includingthe monitored flow rates, corresponding stabilities, and total deliveredfluid dosages. The log files may also include other operationalparameters, such as user provided inputs. These log files may beincluded in a patient's medical history files. In some embodiments, aremote networked computer may monitor the device and generate the logfiles. The log files may be provided to and archived by other systems,such as cloud-based storage systems.

Although many embodiments included herein are discussed in the contextof delivering fluids through an infusion set, it should be understoodthat the present invention is not so limited. The present invention maybe used in any context where fluids are being transported in the form ofindividual drops, for at least a portion of the total distance that thefluid is being transported. For instance, the present invention may beemployed in any context where fluids drops are detectable. Examplesinclude, but are not limited to fluid flowing through a drip chamber, anozzle, a valve, an aperture, or the like. Such contexts include, butare not limited to industrial uses, governmental/academic/industrialresearch, and the like.

FIG. 1A shows an embodiment of flow rate monitoring device 100 adjacentto infusion set 190. In some embodiments, infusion set 190 may be agravity fed infusion set, although the present invention is not soconstrained. For instance, other means of inducing drop flow through apathway, such as a pump, may be employed in various embodiments. In atleast one of the various embodiments, flow rate monitoring device 100may be a handheld device. Flow rate monitoring device 100 includesdisplay unit 102. Display unit 102 may provide a user with real timedata based on at least the monitored flow of fluid through infusion set190. Although not shown in FIG. 1A, some embodiments may also include anaudio interface, such as an audio speaker. An audio interface mayprovide the user with audio information, such as an audible alert whenthe monitored flow rate is outside of a specified range.

Monitoring device 100 includes user input interface 106. User inputinterface 106 may enable a user to provide inputs to the device such as,but not limited to, target flow rate, tolerance ranges, drip factors,lag times, lockout times, stability ranges, alarming functionality,display units, fluid types and the like. In some embodiments, inputinterface 106 may include buttons, alpha-numeric keypads, and the like.In some embodiments, input interface 106 may be integrated with displayunit 102 by employing a touch sensitive display unit. Although notshown, in at least some embodiments, monitoring device 100 may includean audio input device, such as a microphone. Some embodiments mayinclude voice recognition software so that a user may provide inputsthrough the audio input device. Monitoring device 100 includes coupler104. Coupler 104 enables affixing or attaching monitoring device 100 toinfusion set 190.

Infusion set 190 includes fluid source 191. Fluid source 191 may be anIV bag. Infusion set 190 may include a suspension means 193, such as aloop or hook attached to fluid source 191. Infusion set 190 may besuspended in a gravity field by employing suspension means 193. Thesuspension of infusion set 190 allows gravity to induce fluid flowthrough infusion set 190. When affixed to fusion set 190, monitoringdevice 100 may be suspended along with infusion set 190. In at least oneof the various embodiments, coupler 104 may include a clip.

Infusion set 190 may include drip chamber 192. Due to gravity, fluidfrom fluid source 191 flows through drip chamber 192. Also, infusion set190 may be enabled so that as long as the flow rate through infusion set190 is below a critical threshold, the fluid flowing through dripchamber 192 is in the form of individual fluid drops. If the fluid flowrate is above the critical threshold, fluid flowing through drip chambermay become a continuous stream of fluid.

Some elements of infusion set 190 may be characterized by a drip factor.Drip factors depend upon physical characteristics of specific elementsof infusion set 190, such as drip chamber 192 and tubing components suchas fluid output 198, and combinations thereof. Drip factors correspondto the volume of fluid in each individual fluid drop that flows througha drip chamber of the specific infusion set. Drip factors may beexpressed in units of gtt/mL, or drops per milliliter (mL) of fluid. Forinstance, for 1 mL of fluid to flow through an infusion set with a dripfactor of 10 gtt/mL, 10 individual drops of fluid must flow through thedrip chamber. Exemplary, but non-limiting, drip factor valuescorresponding to the combination of the various elements of infusion set190 may include 10, 15, 20, and 60 gtt/mL. Throughout the presentdisclosure, references to an infusion set's drip factor may refer to thevalue of the drip factor corresponding to the combination of the variousinfusion set elements that a drip factor depends upon.

In some embodiments, drip factors may be expressed in alternative units,such as mL/gtt. In other embodiments, the drip factor may be expressedin drops per unit mass or weight if the density of fluid is known. Dripfactors may also be expressed in mass or weight per drop. It isunderstood that the present disclosure is not limited to such exampledrip factors, and may accommodate any other appropriate values, units,or alternative ways to express or measure drip factors.

A flow rate of drops through drip chamber 192 may be converted to afluid flow rate and vice versa based on the drip factor corresponding toinfusion set 190. Additionally, a total number of drops, or accumulatedflow of fluid may be determined by integrating or determining a sum ofthe flow rate of drops or fluid flow rate respectively, over successivepoints in time.

Infusion set 190 includes user handle 194 and roller clamp 196. Byvarying the position of roller clamp 196 along an edge of user handle194, the combination of user handle 194 and roller clamp 196 enables auser to control the flow rate of individual fluid drops through dripchamber 192, and thus the flow rate of fluid through infusion set 190.Infusion set 190 includes fluid output 198. Fluid output 198 deliversfluid, originating at fluid source 191, to the intended target, and atthe flow rate corresponding to the position of roller clamp 196.

FIG. 1B shows flow rate monitoring device 100 attached to infusion set190 by employing coupler 104. In some embodiments, monitoring device 100may be attached to infusion set 190 by attaching or affixing monitoringdevice 100 to the drip chamber, which is hidden from view by monitoringdevice 100.

In some embodiments, including at least embodiments discussed in view ofFIGS. 8A, 8B, and 8C, at least a portion of the drip chamber may bevisible to a user when the monitoring device is affixed to the infusionset. Providing the user visibility to at least a portion of the dripchamber during operation of the monitoring device may enable the user tovisually inspect fluid drops within the channel. In at least one of thevarious embodiments, the monitoring device is affixed to the chamber byemploying a trench or channel that provides the user visibility to atleast a portion of the drip chamber. In some embodiments, when infusionset 190 is suspended or otherwise repositioned, monitoring device 100remains affixed to the drip chamber.

FIG. 2 shows a top-down view of an embodiment of flow rate monitoringdevice 200 affixed to drip chamber 292. Monitoring device 200 includesdevice body 250. Monitoring device 200 includes cavity 258. In someembodiments, cavity 258 may be a cavity, hole, trench, depression, oraperture within device body 250. In some embodiments, cavity 258 mayinclude at least one inner surface.

When monitoring device 200 is attached to drip chamber 292, drip chamber292 may be positioned within cavity 258. In at least one embodiment,cavity 258 may be configured and arranged to receive at least a portionof drip chamber 292. The at least one inner surface of cavity 258 mayprovide a gripping or otherwise frictional force that grips an outersurface of drip chamber 292. This gripping force may enable stabilizingthe monitoring device 200 about drip chamber 292.

In some embodiments, the fit between the outer surface of drip chamber292 and inner surface of cavity 258 may be snug and lack gaps. As shownin FIG. 2, in some embodiments, gaps between at least portions on theouter surface of drip chamber 292 and inner surface of cavity 258 mayexist when monitoring device 200 is affixed to drip chamber 292. In someembodiments, monitoring device 200 may accommodate drip chambers ofvarying shapes and dimensions by outfitting the inner surface of cavity258 with at least one of a compressible gripping material, cammingdevice, or a textured portion.

Monitoring device 200 includes source 210 and detector 212. Source 210may be enabled to emit EMR. In some embodiments, the operation of source210 may allow for controlling at least the timing and/or the intensityof the emission of EMR from source 210. Detector 212 detects the EMRemitted by source 210 and generates a corresponding signal. In someembodiments, source 210 may be an LED. In some embodiments, source 210may be enabled to emit EMR within a specified range of wavelengths orfrequencies. In some embodiments, source 210 may be an infrared emittingdiode (IRED).

In various embodiments, detector 212 may be a photodiode. Detector 212may be enabled to detect the specified range of wavelengths orfrequencies of EMR emitted by source 210. In some embodiments, detector212 may be more sensitive to the specified range of wavelengths emittedby source 210 than to other wavelengths. For instance, if source 210emits IR EMR, then detector 212 may be enabled to generate a moresensitive signal in the presence of IR EMR, than in the presences ofother wavelengths of EMR, such as visible light.

In some embodiments, source 210 and detector 212 may be in oppositionalong the inner surface of cavity 258. When aligned in opposition,source 210 and detector 212 form an optical path across cavity 258. EMRemitted by source 210 and travelling along the optical path may bedetected by detector 212. Such an optical path is shown across cavity258 by the dotted line.

In some embodiments, drip chamber 292 may be at least partiallytransparent, semi-transparent, or translucent to the wavelengths of EMRemitted by source 210. When monitoring device 200 is affixed to dripchamber 292, an optical path across drip chamber 292 is formed. If nofluid is within the optical path, then at least a portion of the EMRemitted by source 210 is detected by detector 212. The portion of EMRemitted by source 210 and detected by detector 212 may generate abaseline detector signal, as will be described in conjunction with FIGS.5A and 5B, below.

At least a portion of device body 250 may be configured as a clip, suchas a tension- or spring-loaded clip. A spring loaded clip may be openedby overcoming the tension with an external force, such as a user openingthe clip. In the absence of such an external force, the clip may be in aclosed state. When drip chamber 292 is positioned within cavity 258, thetension or spring force of the clip may provide a stabilizing force toaffix monitoring device 200 to drip chamber 292.

To provide leverage to a user in assistance in opening the clip, one ormore clip handles 252 may be included with device body 250. In someembodiments, spring 256 may provide at least a portion of the force thatcloses the clip and affixes device 200 to drip chamber 292. Duringopening and closing of the clip, at least a portion of the clip maypivot about hinge 254.

FIG. 3 provides an exploded view of flow rate monitoring device 300 withdrip chamber 392 positioned within the optical path 320 between source310 and the corresponding detector (hidden from view). The dotted linedemarcates optical path 320.

Drip chamber 392 is configured and arranged such that fluid enteringdrip chamber 392 from the top, drips as individual drops, and forms apool of fluid at the bottom of drip chamber 392. Fluid in the pool thenflows out of drip chamber 392 and into fluid output 398. Fluid flowingthrough fluid output 398 is ultimately delivered to the target.

During steady state operation of an infusion set, the volume of the poolof fluid at the bottom of drip chamber 392 remains approximatelyconstant. In such steady state operation, the rate of fluid delivered tothe target through fluid output 398 (in units of mL per unit time) maybe determined based on a ratio of the number of fluid drops falling indrip chamber 392 per unit time to an appropriate drip factor in units ofgtt/mL. An accumulated volume of fluid delivered to the target maysimilarly be determined based on a ratio of a total number of fluiddrops that have fallen in drip chamber 392 to the drip factor.

Three individual fluid drops are shown at various points falling fromthe top of drip chamber 392 towards the pool of fluid at the bottom ofdrip chamber 392. The amount of time an individual drop takes from firstbeginning to drop from the top of drip chamber 392 to the time itreaches the pool at the bottom of drip chamber 392 may be referred to asdrop time-of-flight.

Monitoring device 300 is configured and arranged, such that when affixedto drip chamber 392, each fluid drop passing through drip chamber 392will pass through optical path 320 during a portion of the drop'stime-of-flight. Fluid drop 393 is shown within optical path 320. Thetime period during which a drop is within optical path 320 may bereferred to as the drop's line-of-sight period. The length of a drop'sline-of-sight period may be referred to as the drop's line-of-sighttime.

In some embodiments, the fluid drops passing through drip chamber 393are not completely transparent to at least a portion of the EMRwavelengths emitted by source 310. At the very least, the combination ofdrip chamber's 392 walls and fluid drop 393 is less transparent to theemitted EMR than drip chamber's 392 walls without fluid drop 393 inoptical path 320. Thus, during the drop's line-of-sight period, fluiddrop 393 will at least partially inhibit EMR emitted from source 310from travelling across optical path 320. For instance, fluid drop 393may partially obscure or refract EMR within optical path 320 during itscorresponding line-of-sight period.

Because EMR emitted from source 310 will be at least partially inhibitedduring fluid drop's 393 line-of-sight period, a response of the detectorwill vary, producing a signal different than that of the signal producedwhen no fluid is within optical path 320. The signal produced by thedetector when fluid is not within optical path 320 may be referred to asthe detector's baseline signal.

As provided in more detail below in regards to FIGS. 5A and 5B,monitoring device 300 may be enabled to use the varying signal generatedby the detector to detect in real time, each individual fluid drop as itpasses through drip chamber 392. Based on at least the detection of eachindividual fluid drop, monitoring device 300 may be enabled to determinea total number of fluid drops that have passed through drip chamber 392.By applying the appropriate drip factor to convert number of drips intovolume of fluid, monitoring device 300 may determine a total volume offluid delivered to the target through fluid output 398.

In various embodiments, monitoring device 300 may be enabled todetermine the amount of time between each successive detected fluid dropin drip chamber 392. By detecting a plurality of individual drops overtime, monitoring device 300 may determine a fluid drop rate, such as thenumber of drops per unit time. By applying the appropriate drip factor,monitoring device 300 may determine a volumetric fluid flow ratedelivered to the target through fluid output 398. As provided in moredetail with regards to FIG. 6, monitoring device 300 may determine arolling average and an associated stability of the number of drops perunit time and the volume of fluid per unit time.

In at least one of the various embodiments, monitoring device 300 maydetermine if a determined drop or volumetric flow rate falls outside ofa specified range, such as +−10% of a nominal or target value. Suchinstabilities may occur when a patient changes positions, the IV bagchanges positions, tubing pressure changes, the position of a rollerclamp is accidently altered, the infusion set becomes clogged, the IVbag is depleted and such.

Monitoring device 300 may provide a user with these determinations andadditional information by employing display unit 302. In someembodiments, monitoring device 300 may provide alerts to a user. Suchalerts may be triggered when determinations, such as instabilities in adrop or fluid flow rate, do not match target values within a specifiedrange. Alerts may be provided when an accumulated total target volume offluid has been delivered or the total target volume has been exceeded.Alerts may be provided through display device 302 and/or through anaudio interface, such as a speaker. In at least some embodiments, alertsprovided to the user may include visual alerts, such as alerts providedby an LED that emits at least optical frequencies of EMR or other suchsources of light, including light bulbs or optical lasers. Alerts may beprovided by rapidly pulsing audio or visual signals, such as a strobelight or a siren. Users may provide monitoring device 300 with targetvalues for such metrics that are monitored, through user inputinterfaces, such as user input interface 106 of FIGS. 1A and 1B.

Some embodiments may be networked to remote devices and supply users ofthe remote devices with such information and alerts. Some embodiments ofmonitoring device 300 may include non-volatile memory devices thatenable the creation of log files including one or more metricsdetermined and monitored by monitoring device 300. Log files may includevalues of user inputs, such as target volume or target flow rates. Logfiles may include other data, such as the amount of time that fluid wasflowing through a drip chamber, time stamps for each individuallydetected drop, drop waveforms, and other diagnostics, acquired data, andoperating conditions.

By employing a networked monitoring device, data may be provided toremote devices. Such provided data may be used by remote devices togenerate log files. These log files may be archived for future accessand may become part of a patient's medical history. These log files maybe used as input data for clinical tests or other research or industrialpurposes. For example, log files may be employed in the production of orresearch regarding energy sources, such as biofuels.

FIG. 4 shows a block level diagram of components included in variousembodiments of flow rate monitoring devices described throughout thepresent disclosure. One such monitoring device may be monitoring device100 of FIG. 1. In some embodiments, a monitoring device may include aprocessor device. In at least one of the various embodiments, aprocessor device may include a programmable microcontroller, such asmicrocontroller 416.

A monitoring device includes a source. In some embodiments, a source mayinclude LED 410. LED 410 may be an infrared (IR) LED, such as an IRED.At least one terminal of LED 410 may be tied to ground. A monitoringdevice may include a detector. In some embodiments, detector may includephotodiode 412. Photodiode 412 may have a greater sensitivity to IRwavelengths than to wavelengths within the visible light spectrum. Insome embodiments, sense resistor 414 may be used in conjunction withphotodiode 414. Sense resistor may be between photodiode 412 and ground.

In some embodiments, microcontroller 416 may control the operation of atleast one of LED 410 and photodiode 412. Such controls may includecontrolling a pulsing of biasing currents used in the operation of LED410 and photodiode 412. Furthermore, microcontroller 416 may monitor oneor more signals from photodiode 412, including at least an EMR detectionsignal generated by photodiode 412 and in response to detecting EMRemitted from LED 410.

The EMR detection signal may be a digital signal. However, in at leastsome embodiments, the EMR signal may be an analog signal. If the EMRdetection signal is an analog signal, the EMR detection signal may bedigitized before being provided to microcontroller 416. In otherembodiments, the EMR detection signal may be provided to microcontroller416 as an analog signal. In some embodiments, no pre-amplification maybe required of the EMR detection signal prior to being provided tomicrocontroller 416. In these embodiments, the ability to providemicrocontroller 416 the EMR detection analog signal withoutpre-amplification reduces the total number of components required formanufacturing a monitoring device. This reduction in component count mayresult in reducing cost and/or complexity of the monitoring device.

Monitoring devices may operate in a “continuous mode” or a “samplemode.” In some embodiments, at least one of LED 410 and photodiode 412may be operated at a 100% duty cycle during the operation of themonitoring device. In these “continuous mode” embodiments, fluid dropdetection measurements may be made continuously.

In order to reduce operating power requirements, at least one of LED 410and photodiode 412 may be operated at less than a 100% duty cycle. Insuch “sample mode” embodiments, fluid drop detection measurements may bemade periodically or in samples rather than continuously. Thus, samplemeasurements may be made at a predetermined frequency.

The amount of time an individual fluid drop, such as fluid drop 393 ofFIG. 3, is within the monitoring device's optical path, such as opticalpath 320, may be referred to as the drop's line-of-sight time. In someembodiments, time between consecutive samples, or sample period, may beless than a drop's line-of-sight time. In at least one of the variousembodiments, the sample period may be significantly less than a drop'sline-of-sight time. As will be shown in conjunction with FIGS. 5A and5B, employing a sample period significantly less than a drop'sline-of-sight time allows for the generation of a drop's waveform ortime profile.

In some embodiments, LED 410 and photodiode 412 are operated for only afraction of a sample period for each sample measurement. For instance,for a sample frequency of 1 kHz, a sample measurement is obtained every1 millisecond (ms). In some embodiments, 1 ms is significantly less thanany individual drop's line-of-sight time. To sample the transparency ofoptical path 320 during a single sample measurement, bias current issupplied to LED 410 and photodiode 412 for a length of time referred toas an operation time. The operation time may be less than the sampleperiod. For instance, for a sample period of 1 ms, the bias current maybe supplied to LED 410 and photodiode 412 for only about 10microseconds. An operation time of 10 microseconds results in anoperational duty cycle of (10 microsecond)/(1 ms), or 1%.

“Sample mode” embodiments may enable monitoring devices withsignificantly lower power consumption requirements because biasingcurrents are only being supplied to the source and detectors for a smallfraction of the time. Operation times may be based on one or morecharacteristics such as source and detector rise and fall times,operating speed of a processor device, optical transparency of the fluidand/or drip chamber walls, length of drip chamber, response times ofvarious components and/or circuits included in the monitoring device,and the like.

It is understood that the numerical values for sample frequency, sampleperiod, operation time, as well as all other numerical values usedherein are for illustrative purposes only, and the disclosure is not soconstrained by the values provided herein. Rather, these values arechosen for their illustrative purposes. In some embodiments, sampleperiods and the like may be varied to account for detector responsetimes, length of drip chambers, characteristics of the fluid,characteristics of sources/detectors such as rise/fall times, and thelike.

In some embodiments, microcontroller 416 may control the pulsing ofbiasing currents for LED 410 and photodiode 412. Some embodiments may beenabled to operate in both “continuous” and “sample” modes. In suchembodiments, a user may be enabled to select which mode to operate in,as well provide programmable operational parameters such as samplingfrequency, duty cycles, and the like.

Various embodiments may include a power supply. The power supply maysupply power to various components, such as microcontroller 416, as wellas other components. In some embodiments, the power supply may be aninternal power supply, such as battery 418. Battery 418 may bereplaceable. Furthermore, battery 418 may be rechargeable. Someembodiments may include more than one battery to provide redundancy.Some embodiments may account for an external power supply, such as wallmounted sockets. Some embodiments may be enabled to employ both anexternal and an internal power supply, depending on the needs of a userand the context of operation. For instance, some monitoring devices maybe powered by a wall socket, and also include a backup battery in theevent of a loss of power to the wall socket. In at least one of thevarious embodiments, the power source may include a photovoltaic cell,such as a solar cell.

Monitoring devices may include display unit 402. Display unit 402 may beemployed to provide information to a user. Such information may include,but is not limited to, determined fluid flow rates, fluid drop rates,percentage or absolute amount of battery power remaining, the dripfactor currently used by the monitoring device, total accumulated drops,total accumulated fluid flow, and the like. Microcontroller 416 maycontrol at least a portion of display unit 402.

Monitoring devices may include a user input interface. A user inputinterface may include button inputs 406. Button inputs 406 may be usedby a user to provide the device with various user inputs, such as dripfactor, target fluid drop rate, target fluid flow rate, target totalaccumulated fluid flow, etc. In some embodiments, a user may togglebetween “continuous mode” and “sample mode” of operation by employingbutton inputs 406. In some embodiments, a user may provide a monitoringdevice with a target duty cycle or other such input information byemploying button inputs 406.

Monitoring devices may include an audio interface, such as alerttransducer 408. Alert transducer 408 may be a speaker used to provideaudio alerts and other audio information to a user. Microcontroller 416may communicate with display unit 402, button inputs 406, and alerttransducer 408 and supply inputs and outputs to these and other devices.

Although not shown, it is understood that various other components, suchas charge pumps, may be used in embodiments. Digital memory devices maybe included in various embodiments. Memory devices may be volatile ornon-volatile memory devices. Memory devices may include, but are notlimited to RAM, ROM, EEPROM, FLASH, SRAM, DRAM, optical disks, magnetichard drive, solid state drives, or any other such non-transitory storagemedia. Memory devices may be used to store various information,including but not limited to programmable user inputs, monitoredmetrics, log files, or operational parameters.

Although not shown, it is understood that various embodiments ofmonitoring devices may include a network transceiver device. Suchnetwork transceivers may be enabled to communicate with other devicesover a wired network or a wireless network. Such transceivers may beenabled with Wi-Fi, Bluetooth, cellular, or other data transmission andnetworking capabilities. In such embodiments, monitoring devices may beenabled to communicate with other devices. These other devices mayinclude remote computer devices, such as servers, clients, desktops, andmobile devices.

Users may supply inputs to the monitoring device by the remote use ofthese networked computer devices. Furthermore, users may be enabled tomonitor, in real time, information supplied by the monitoring devices,through the use of remote computing devices. Health care providers maybe enabled to remotely monitor patients from afar. For instance, doctorsor nurses, in one area of a hospital may be able to remotely monitor theIV drips for patients located in other areas of the hospital. Mobiledevices, such as tablets or smartphones may be employed for such remote,real-time monitoring.

Also, the networking capabilities may enable data logs for patients tobe generated and archived. These data logs, or log files, may becomepart of a patient's medical history. Furthermore, these log files may beemployed as evidence regarding a standard of care provided to thepatient.

FIGS. 5A and 5B show time series plots of generated waveforms based onEMR detection signals. In some embodiments, a waveform may include atemporally ordered plurality of points, each corresponding to a detectorsignal. Each point in a waveform may include a time coordinate and adetector signal coordinate. Because the points are temporally ordered,characterization of points as prior, current, and subsequent point arewell defined. Also, a distance between points, such as a time distancebetween points is well defined.

In FIGS. 5A and 5B, the unprocessed EMR detection signals may be analogsignals from a detector, such as photodiode 412 of FIG. 4. The analogsignals may be digitized prior to the generation of waveforms. In someembodiments, the digitization may occur within a processor device, suchas microcontroller 416 of FIG. 4. A digitization process may employ anAnalog-to-Digital Converter (ADC), internal to microcontroller 416. FIG.5A shows a pre-processed drop waveform 522. The x-axis represents thetime of a sampled detector reading in milliseconds. The y-axisrepresents an ADC value based on the signal generated by the detector ateach sampled time.

In FIG. 5A, the start of a fluid drop, such as fluid drop 393 of FIG. 3,entering an optical path, such as optical path 320 of FIG. 3, is markedat approximately 20 ms. Furthermore, the time that the fluid drop exitsthe optical path is marked at approximately 36 ms. Thus, the dropline-of-sight time is approximately 16 ms.

Note the variance in value of waveform 522 during the line-of-sightperiod. A two peak structure may be characteristic of some fluid drops.Note the two peak structure in waveform 522, where the first peak ismarked at approximately 27 ms, and the second peak occurs atapproximately 29 ms. This variance in the digitized signal value is dueto the fluid drop inhibiting EMR emitted by a source, such as LED 410,from flowing across the optical path.

Also note the baseline signal, with an ADC count of approximately 183,corresponding to the uninhibited flow of the EMR across the opticalpath. Noise fluctuations are also shown on drop waveform 522. In someembodiments, these noise fluctuations may be filtered using hardwareand/or software based filters.

In some embodiments, drops may be detected by employing a processordevice, such as microcontroller 416 of FIG. 4, to analyze drop waveformsin real time, such as exemplary drop waveform 522. Some embodiments mayutilize a method of analyzing drop waveforms that includes a comparisonof the waveform at each sample to an absolute threshold, such as acalibration threshold or an averaged or filtered value of the baselinesignal, shown in waveform 522.

Other embodiments may compare at least a portion of the points inwaveform 522 to other points in waveform 522. In such embodiments, thedetector signal at various sample times may be employed to generatedifference waveforms. Such difference waveforms may result in differencesignals that are characteristic to the detection of fluid drops. Forinstance, the detector signal (or ADC count) at each sample may becompared to the detector signal (or ADC count) from a prior sample. Anamount of time between the time corresponding to the current sample andthe time corresponding to the prior sample may be referred to as lagtime.

A lag time difference waveform may be determined by first generating apre-processed waveform, such as waveform 522. Subsequent to generatingpre-processed waveform 522, a difference between each point included inat least a portion of the points on pre-processed waveform 522 and aprior point on pre-processed waveform 522 may be determined, where thetwo points used to generate the difference are separated by a timedistance equal to the lag time.

FIG. 5B shows lag time difference waveform 524, which is a simpledifference waveform. Simple difference waveform 524 was generated usinga lag time equivalent to the sample period. In other words, eachinstance of the detector signal is compared to the immediate priorsample. For simple difference waveform 524, the sample period is equalto the lag time (1 ms) and the drop line-of-sight time is approximately16 ms. Detecting a fluid drop from a simple difference waveform mayprove difficult because unless the absolute values of the timederivative of the pre-processed waveform 522 are large enough, theliquid drop signal resulting from a simple difference waveform may besmall, as shown in simple difference waveform 524.

Other choices of lag time may be more advantageous. In order to producea better signal-to-noise ratio, a larger lag time may be employed. Suchlarger lag times may produce difference signals more characteristic of afluid drop, resulting in a suppression of false positive and falsenegative fluid drop detections. Some embodiments may employ a lag timeapproximately equal to half a drop's line-of-sight time. Such a valuemay result in a larger time difference signal. Such a value may enhancethe likelihood of successfully detecting a fluid drop. This is becausethe peak structure of the unprocessed waveform is compared to thebaseline signal of the waveform, resulting in a larger time lagdifference signal that is indicative of a fluid drop.

For instance, lag time difference waveform 526 was generated fromwaveform 522 by using a lag time of 8 ms. Note the amplitude of thesignals in lag time difference waveform 526 with simple differencewaveform 524. The greater signal amplitude of time difference waveform526 may result in better drop detection. Also note both the positive andnegative structure of waveform 526. The negative and positive peaks oflag time difference waveform 526 result from the comparison of the peakstructure of pre-processed waveform 522 in comparison to the baselinedetector signal prior to and subsequent to the drop's line-of-sightperiod, respectively. This adjacent negative and positive peak structureassociated with an appropriate choice of lag time may be acharacteristic signal of a fluid drop detection. Thus, such appropriatechoices for a lag time may result in a better signal to noise ratioand/or an increase in drop detection accuracy; including at leastsuppressing both false positive and false negative detections.

Waveform 526 may not be sensitive to long-term changes of signal value,but it largely retains the high signal to noise ratio of waveform 522.The waveform 522 may exhibit a large signal difference between thesignal baseline and the negative peak. However, the specific ADC countvalues of the baseline and the peak will vary based on a variety offactors including but not limited to source brightness, shape, andmaterial of the drip chamber, ambient light, drip position, andcondensation on the drip chamber. No single threshold value fordetecting a drip will be robust to changes in these environmentalfactors.

The waveforms 524 and 526 are not sensitive to long-term changes insignal value, so the above factors do not affect the signal. However,the signal to noise ratio of waveform 524 is low, which may lead toproblems with false positives and negatives. Waveform 526 is notsensitive to long-term changes of signal value, but it largely retainsthe high signal to noise ratio of waveform 522.

In some embodiments, the lag time is chosen to be longer than a falland/or rise time of the detector. In at least one of the variousembodiments, an employed lag time is longer than several sample periods,but shorter than the drop line-of-sight time. For instance, a lag timeof 8 ms is shorter than a line-of-sight time of 16 ms (and isapproximately half the drop's line-of-sight time), but longer than asample period of 1 ms, as shown in waveforms 526. A lag time longer thanthe drop line-of-sight time may fail to detect fluid drops. In someembodiments, the lag time may be varied depending on the particular useof a monitoring device. In some embodiments, a user may be enabled toprovide a lag time to use during a particular operation.

In some embodiments, a lag time difference waveform, such as lag timedifference waveform 526, generated based on an appropriate lag timevalue, may be employed in detecting each individual drop. By employingat least a processor device, such as microcontroller 416 of FIG. 4, dropdetection may be performed in real time, as the drop is falling in thedrip chamber. Lag time difference waveforms may be analyzed to detectthe fluid drops. In various embodiments, drop detection may be based onthe shape of a plurality of lag time difference waveforms generated byemploying an appropriate lag time value.

Some embodiments may employ a lockout method to enable a vetoing offalse positive drop detections. It is possible for a detector signal topresent a drop profile at more than one instant in time. For instance,if the time difference between the detection of a first drop and asecond drop is below a lockout threshold, then at least one of thedetections is determined as a spurious detection. A spurious detectionevent may trigger the vetoing of at least one of the two dropdetections.

In some embodiments, the waveforms corresponding to vetoed, or lockoutdetections, may be included in a log file for future analysis. In someembodiments, the detection of a plurality of lockout events within aminimum amount of time may signal that the drop rate is unstable, orthat the drops or flowing too quickly within the drip chamber to enableindividual drop detections. Some embodiments may provide a user with anaudio or visual alert in the event of one or more lockout events.

The lockout threshold or period may be chosen to be longer than a dropline-of-sight time, but shorter than an average drop rate. In someinstances, a user may supply the lockout threshold. In some embodiments,the lockout threshold may be varied to account for a current averagedrop rate.

FIG. 6 shows embodiments of method 630 for operating a monitoringdevice. Methods, such as method 630, may be performed by a processordevice, such as microcontroller 416 of FIG. 4. A processor device mayexecute instructions that perform actions. At block 631, a drop isdetected within a drip chamber, such as drip chamber 392 of FIG. 3, attime t. The drop may be detected using various methods, such as, but notlimited to, the various embodiments discussed in reference to FIGS. 5Aand 5B. If the drop is not vetoed as a lockout event, then method 630may proceed to block 632.

At block 632, the detected drop is added to a drop history buffer. Insome embodiments, the buffer may be stored in at least a memory deviceincluded in the monitoring device. The memory device may be a volatileor non-volatile memory device. Adding the detected drop to the drophistory buffer may include adding a detection time to the buffer. Insome embodiments, a drop line-of-sight time corresponding to the addeddrop may be added to the buffer. In at least one of the variousembodiments, at least a portion of the detector signal associated withthe added drop may be added to the buffer. At least one waveform, suchas any of 522, 524, or 526 of FIGS. 5A and 5B may be added to thebuffer. A total drop count associated with the detected drop may beadded to the buffer. In some embodiments, the buffer includes aplurality of previously detected drops.

If a monitoring device is operated in a manual transition mode, method630 branches to manual transition method 633 and proceeds to block 635.If the monitoring device is operated in automatic transition mode,method 630 branches to automatic transition method 641 and proceeds toblock 642. In at least one of the various embodiments, a user may beenabled to select manual transition mode or automatic transition mode byemploying a user input interface, such as user input interface 106 ofFIGS. 1A and 1B.

At block 635 and block 642, the drop history buffer is trimmed to aspecified time span. The specified time span may depend on an availablesize of the buffer, such as the amount of memory allocated for thebuffer. The buffer size may be resized to accommodate the specified timespan. If the addition of the drop detected at block 631 to the bufferwould induce a buffer overflow, at least one drop may be removed fromthe buffer. The buffer may be a first-in first-out (FIFO) buffer, sothat the removed drop is the least recent drop in the drop historybuffer. The buffer may be trimmed or expanded so that a specifiedmaximum or minimum number of drops are included in the history buffer.

At block 636 and block 643, a check is performed to insure minimumintervals are available for further determinations. For instance, if arolling drop rate average is to be determined, a check may be performedto insure that a minimum number of drops are included in the buffer. Insome embodiments, a check may be performed to insure that a minimum timebetween the most recent and least recent drops in the buffer exists. Insome embodiments, a check may be performed to insure that a minimum timebetween successive drops in the buffer exists. These and other checksmay be performed to insure the statistical significance or stability offurther determinations.

In some embodiments, a rolling average may be determined. In at leastone of the various embodiments, a rolling average may be based on aratio of a total number of detected drops in the buffer to a totalamount of time between the detections. For instance, a total amount oftime between the detections may be based on a difference of thedetection time of the most recent drop in the buffer and a detectiontime of the least recent drop in the buffer. In some embodiments, therolling average may be determined in various units. For instance, therolling average may be determined in drops per unit time, or timebetween drops. In at least one of the various embodiments, the rollingaverage may be determined in volume of fluid per unit time or time perunit of volume. It is to be understood that other methods fordetermining a rolling average may be employed.

If a user has indicated to measure the drop rate, then method 633proceeds to block 638. For instance, a user may indicate to measure thedrop rate by activating a measure mode through a user interface, such asuser interface 106 of FIGS. 1A and 1B. At block 638, the determinedrolling average may be displayed. Displaying the rolling average may beenabled by employing a display unit, such as display unit 102 of FIGS.1A and 1B.

If a user has not indicated to measure the drop rate, then method 633proceeds to block 640. At block 640, the most recent time interval maybe displayed. The most recent time interval may be based on at least thedetection times of the two most recent drops in the drop history buffer.

At decision block 644, a determination is performed based on at least adrip stability. The drip stability may be determined based on acomparison of a plurality of distances between detection times ofsuccessive drops included in the drop history buffer. If the dripstability is less than a predetermined threshold, method 641 proceeds toblock 648. An illustrative, but non-limiting or non-constraining valueof a stability threshold is a variation of 12.5%. At block 648, as withblock 640, the most recent time interval may be displayed. Otherwisemethods 641 proceeds to decision block 645.

At block 645, a determination is performed based on whether the drophistory buffer spans a predetermined length of time. If the buffer doesnot span the predetermined length of time, method 641 proceeds to block648. Otherwise, method 641 proceeds to decision block 646.

At block 646, a determination is performed based on whether the bufferhas a predetermined minimum threshold of intervals. If the buffer doesnot have the predetermined threshold of intervals, method 641 proceedsto block 648. Otherwise, method 641 proceeds to block 647. At block 647,the determined rolling average is displayed.

In some versions, it may be desirable to have two different rollingaverage time periods, including a first rolling average period which iscalculated over a longer period of time than a second rolling averageperiod which is calculated over a shorter period. The longer theaveraging period used, the smoother the reported rate will be. Thus, thelonger first period of time will produce a rolling average which issmoother, and less prone to report deviations in the rolling averagebased on deviations in one or a small number of drops. Likewise, theshorter second period of time will likely have greater variation andwill more readily increase or decrease in value based on one or a smallnumber of deviant drops. Each of the first and second rolling averageperiods have distinct but different value. If the averaging interval istoo long, it becomes difficult for a user to adjust and set the ratebecause it takes too long for the actual rate change to be reflected inthe displayed rolling average value. On the other hand, if the intervalis too short, then an out-of-range alarm may sound based on one or asmall number of outlier drops that are not indicative of the trueaverage drop rate. The period of time used for rolling averages may be afunction of intervals of time, or may be based on specific numbers ofdetected drops. In one example, the first or longer averaging period isdetermined based on a rolling average over 64 drops while the shorterperiod is taken over 16 drops.

In one version, to provide for both modes, the system incorporates twodifferent averaging periods depending on the system mode. In oneexample, the system uses the status of the alarm to determine the user'sintention and to thereby select which of the rolling average periods areto be applied. When the alarm is not enabled, the system presumes thatthe user may be attempting to adjust the rate, and thus a shorteraveraging period is chosen to provide timely rate updates on thedisplay. Once the user enables the alarm, the system presumes that theuser has done so because an appropriate rate has been found andstabilized, and thus the system engages the longer averaging period toprovide a smoother display while the alarm is enabled.

In one example of the invention, an alarm includes an alarm threshold inwhich the alarm is triggered by a drop which is plus or minus thirteenpercent of the selected flow rate (or the rolling average rate).Preferably, when the alarm sounds based on such a drop (or multipledrops), the system automatically switches to the shorter averaginginterval to enable the user to adjust the flow rate to the desiredlevel. Once the flow rate is back within tolerances, a timer is used toensure the flow rate stays within the alarm thresholds. When the rate iswithin the plus or minus thirteen percent tolerance for at least thirtyseconds, the system again employs the longer averaging period andthereby reverts to the smoother rate display.

FIG. 7 shows one embodiment of device body 750 included in someembodiments of a monitoring device. Device body 750 may be opened andclosed. As shown in FIG. 7, device body 750 is an open state. At least aportion of device body 750 is enabled as a clip that can be opened bythe application of a force. Clip handles 752 may be actuated by anactuating force to open device body 750. Clip handles 752 may provideleverage for a user to provide the actuating force required to opendevice body 750. During an opening or closing operation, portions ofdevice body 750 may pivot about hinge 754.

When the actuating force is not applied to clip handles 752, device body750 may be in its closed state. Spring 756 may supply the force to closethe device. Device body 750 may include a first wing 760 and a secondwing 762. First wing 760 and second wing 762 may be affixed about hinge754. First wing 760 may include a first trench 764. Second wing 762 mayinclude a second trench 766.

When device body 750 is in a closed state, first trench 764 and secondtrench 766 may be aligned to form a cavity, such as cavity 258 of FIG.2. When device body 750 is affixed to a drip chamber, such as dripchamber 292 of FIG. 2, at least a portion of the drip chamber may bereceived by the cavity formed by the alignment of first trench 764 andsecond trench 766. At least one of first trench 764 and second trench766 may include textured material to enable gripping of the dripchamber.

FIGS. 8A, 8B, and 8C show various views of embodiments of flow ratemonitoring device 800. Monitoring device 800 may include display unit802, user input interface 806, and user audio interface 808. Amonitoring device 900 is also shown in FIG. 9 in which the tubing set953 incorporates a mounted sensor device body 953. A monitoring device800 is also shown in FIGS. 18 and 19, as with the device 800 of FIGS.8A-c, incorporating the sensors in the monitoring device while providinga mechanism for attaching the tubing set in the manner of the channelsillustrated in FIG. 9 and described below.

The monitoring device 800 may include an outer case having a channel.Some embodiments may include trench 864. When monitoring device 800 isaffixed to a drip chamber, such a drip chamber 192 of FIG. 1, at least aportion of the drip chamber may fit snuggly in trench 864. At least oneinner surface of trench 864 may include textured material 868 to assistin gripping the drip chamber. In some embodiments, at least one innersurface of trench 864 may include camming device 870 to assist ingripping the drip chamber. In some embodiments, textured material 868and camming device 870 may be in opposition. In at least one embodiment,textured material 868 may be a compressible material that expands andcontracts to accommodate drip chambers of various dimensions. In someembodiments, camming device 870 may be enabled to accommodate dripchambers of various dimensions. Camming device 870 may include ridges orteeth that enhance drip chamber gripping and friction.

Monitoring device 800 may include source 810. Source 810 may bepositioned along at least an inner surface of trench 864. Although notshown, monitoring device 800 may include a detector. Source 810 and thedetector may be in opposition along the inner surface of trench 864 toform an optical path across a drip chamber when monitoring device 800 isaffixed to the drip chamber. This same arrangement is illustrated inFIGS. 18 and 19, and both the source 810 and detector 811 are visible inthe elevational view of FIG. 19, showing the location of a correspondingdetector in the monitoring device of FIGS. 8A-C.

In at least one of the various embodiments, the channel or trench 864may receive a portion of the drip chamber when monitoring device 800 isaffixed to the drip chamber. In some embodiments, because at least aportion of the channel or trench 864 is open, at least a portion of thedrip chamber is visible to a user during operation of monitoring device800. A user may be enabled to visually or manually inspect the droppingof the individual fluid drops during the monitoring of the fluid flowrate. Because at least a portion of the drip chamber is visible to theuser, some embodiments may provide the user with visual feedback of thedetected fluid drops. Due to visual feedback and in response to thedetermined fluid flow rate provided by the monitoring device, the usermay precisely adjust or vary the flow rate, such as a manual operationof a roller clamp, like roller clamp 196 off FIGS. 1A and 1B, or othersuch adjusting means, to achieve the desired target flow rate.

FIG. 8A shows monitoring device 800 from a front-side view from anoblique angle. FIG. 8B shows monitoring device 800 from a front view.FIG. 8C shows monitoring device 800 from a top view.

FIGS. 9-11 show an alternate version of a monitoring device 900 and asensor device body 950, separated from one another in FIG. 9,interconnected in FIG. 11, and illustrating the sensor device body alonein FIG. 10. In one version of this alternate embodiment, the sensordevice body 950 includes an infrared emitting diode 951, or IRED, and aphotodiode 952, or PD (see FIG. 10), which are positioned about a tubingset 953 in such a way so that drops 954 falling from the top to thebottom of the tubing set will at least partially obscure or refract thebeam 955 which extends along a line of sight from the PD to the IRED.Most preferably, the IRED and PD are attached to a housing 956 formingthe sensor device body, and surrounding the tubing set or at leastextending along diametrically opposite portions of the tubing set. Insome versions, the sensor device body need not have a separate housing,but rather can comprise the tubing set itself, with the variouscomponents mounted to the tubing set. The sensor device body components(such as the IRED and PD) may be electrically connected to contacts 957(best seen in FIG. 10) exposed on the exterior of the tubing set andpreferably formed on a tab or projection 958 extending outwardly fromthe housing. The tubing set contacts 957 are configured to align withreceiving contacts 910 mounted on the separate monitoring device 900which attaches to the drip chamber and sensor device body. As discussedfurther below, the contacts 957 may facilitate the delivery of power tothe housing, and enable data related to the PD or other aspects withinthe sensor device body to be exchanged with the monitoring device.

For simplicity of illustration, the embodiments of FIGS. 9-11 areillustrated without a fluid source. The tubing set and sensor devicebody are illustrated with an exemplary upper receiving tube 963 havingan upper end in the form of a spike for insertion into a fluid sourcesuch as fluid source 191 as illustrated in FIG. 1.

In one version, the housing 956 includes a pair of lateral fins 960, 961which are configured to be received within mating channels 911, 912 ofthe monitoring device, thereby ensuring a snug fit of the housing to themonitor, including the alignment of the sensor device body contacts 957with the monitor contacts 910. Thus, most preferably the sensor devicebody includes structural features that allow it to mount to themonitoring device, and further in which the IRED and PD are mounted onthe sensor device body rather than on the monitoring device. In such aversion, the alignment of the components about the drip tube are notsubject to movement or faulty attachment by a user because they arefixedly mounted in a proper location, diametrically opposite oneanother. The monitoring device 900 may otherwise be substantiallysimilar to, or the same as, other versions of monitoring devicesdescribed above, having for example a display 913, a number of buttons914 or other input/output interface devices, a trench 915 for receivingthe tubing set, and an internal processor and memory for operating themonitoring device. The monitoring device may further be secured in placeeither with a mechanical latch, magnets, other mechanical features.

Most preferably, as noted above, in the embodiment as shown in FIGS.9-11 at least the emitter and detector are fixedly mounted to the tubingset so that their alignment cannot be altered by a user. Thus, forexample, the emitter, detector and power source may be glued or moldedto the drip chamber, or mounted to the housing with the housingpermanently glued or otherwise permanently attached to the tubing set sothat the alignment is fixed in place. As used here, mounting usingscrews or bolts is within the meaning of “permanently attached” becausethey would require a tool for removal, and cannot be removed simply by auser squeezing the handles to urge apart a spring-loaded device, forexample.

In one embodiment, such as illustrated in FIG. 12, a wired tether isemployed to link the tubing set to the monitoring device. One end ofthis tether may interface with the form factor and connector of thetubing set, and the other end may be connectable to a monitoring device,Thus, the tether may serve as an “extension cord,” allowing the sensorand the monitoring device to be separated by some distance. Such a wiredinterface may employ a serial, e.g., RS232, connection, a USBconnection, an Ethernet connection, an 12C connection, an SPI interface,or the like.

As one example, the sensor device body 950 includes a wire 964 extendingfrom the sensor housing 956 and terminating in a coupler 967. Thecoupler is configured to mate with the monitoring device 900, and in oneversion the coupler is formed with an outer shape consistent with thesensor housing as described above, corresponding to the pair of lateralfins 960, 961. Consequently, the coupler is configured to be receivedwithin the mating channels 911, 912 of the monitoring device. Thecoupler further includes contacts such as those corresponding to thetubing set contacts 957 as described above, and which are configured toalign with receiving contacts 910 mounted on the separate monitoringdevice 900. The tethered coupler therefor allows the monitoring deviceto be located at a distance from the tubing set and sensor housing,limited only by the length of the cord or cable 964.

In yet another one embodiment, as illustrated in FIG. 13, an embeddedradio in the tubing set, or more preferably in the sensor device body950 or its housing 956, can also be used to communicate with themonitoring device 900 wirelessly. In one version, the monitoring deviceas described above may include its own receiver, transmitter, ortransceiver in order to send or receive signals to or from the sensordevice body 950 wirelessly. Similarly, the sensor device body 950,preferably within the housing 956, includes a transceiver or equivalentcomponents to enable such communication. In this configuration, thesensor device body may send data related to the monitoring of drips tothe monitoring device, which can then store, analyze, and display thedata accordingly at a remote location.

In one version, the monitoring device may be the same or substantiallysimilar to the monitoring device as described above, other than theinclusion of components to enable wireless communication. In alternateversions the monitoring device may be configured differently, forexample to exclude the trench, contacts, and other features for directreception of the tubing set and sensor device body. In one such case,the monitoring device may be in the form of a personal computer or atablet 920 containing stored programming instructions enabling thereceipt and analysis of the data as described above. In otherembodiments the monitoring device 920 may be a smartphone or otherwireless-enabled device running software for interfacing wirelessly withthe tubing set and sensor device body.

As illustrated in FIG. 13, the sensor device body 950 and monitoringdevice 900, 920 are indicated as communicating wirelessly with oneanother in a direct fashion, for example by using Bluetooth or otherprotocols. For example, a wireless link may include a USB link, aBluetooth link, a Low Power Bluetooth link, a ZigBee link, a NFC link,and/or the like. It should be appreciated that the connection may beless direct, such as over a Wi-Fi or other wireless network, or evenmore remotely over the Internet or other networks.

The devices in FIGS. 12 and 13 illustrate tethered and wirelessconnections between a sensor device body and a monitoring device, inwhich the sensor device body is permanently affixed to the tubing set.In other versions, the wireless or tethered connections may extend froma separate sensor device designed to clip or otherwise attach onto theexterior of standard tubing sets, such as the version as illustrated anddescribed above with reference to FIGS. 2 and 3. This removable devicemay contain a drop sensor, and may be connected with a tether (see FIG.14) or have components allowing it to wirelessly (see FIG. 15)communicate with a separate monitoring device. Such a removable devicemay be generally lighter than the above-discussed all-in-one devices, inwhich the monitoring device and display are incorporated into the sensordevice body and attached to the tubing set directly. Also, such a devicemay enable more secure attachment and better sensor alignment whencompared to an all-in-one device.

Certain embodiments of the present technology also include drop-sensingor other flow rate technologies other than infrared beam detection,including but not limited to RF, optical, and capacitive sensingtechnologies.

In certain embodiments, after receipt of the flow rate data by themonitoring device through wired or wireless means, the data may befurther transmitted through a wired or wireless communications method toa remote monitoring station, which could be elsewhere in a facility orremotely located through a long-distance network. For example, as notedabove, either of the monitoring devices 900, 920 may be located remotelyand in communication with the sensor device body 950 over a wirelessnetwork which may include the Internet.

In additional embodiments, the same electromechanical or wirelessinterface is extended to sensors beyond drip rate measurement, such aspulse oximeters, respiratory or electrocardiac monitors, as well asinterventional devices such as IV flow rate controllers, pumps, or SCDs(sequential compression devices). Thus, the sensor device body may beincorporated into a device other than a tubing set, in which the sensorsmonitor other parameters and convey the data in a fashion as describedabove.

In some versions, these electromechanical or wireless interfaces maycontain a facility allowing such attachments (including theabove-discussed tube sets) to “self-describe” to the monitoring device,which may then display appropriate control and status informationdepending on the nature of the attached sensor or interventional device.

FIG. 16. illustrates a block diagram of the internal components formingan electrical circuit of the preferred sensor device body 950 andmonitoring device 900. The sensor device body includes a source, whichmay be in the form of an LED 410. At least one terminal of LED 410 maybe tied to ground. A detector is also provided, which is preferably aphotodiode 412. Photodiode 412 may have a greater sensitivity to IRwavelengths than to wavelengths within the visible light spectrum. Aresistor 414 may be used in conjunction with the photodiode 414,connected between the photodiode 412 and ground.

In the illustrated example, a microcontroller 416 may control theoperation of at least one of the LED 410 and photodiode 412. In someversions, however, a microcontroller may be omitted from the sensordevice body 950. This may be desirable, for example, in versions inwhich the sensor device body connects directly (such as in FIG. 11) orthrough an optional tether 964 (such as in FIG. 12) to a monitoringdevice 900 having its own microcontroller or microprocessor. Within thisdescription, the term “processor” will generally encompass processors,microprocessors, and microcontrollers. Where a processor is omitted fromthe sensor device body 950, the components of the sensor device body arepreferably arranged for signal communication with, and control by, aprocessor within the monitoring device 900 via the contacts 910, 957, asdescribed above.

The processor (whether in the sensor device body 950 or monitoringdevice 900) may control a pulsing of biasing currents used in theoperation of LED 410 and photodiode 412, and may perform the otherservices as described above with reference to FIG. 4.

As illustrated, the sensor device body includes a source of power, 418,which may include a power supply in the form of an internal powersupply, such as a battery or a cord for AC power. In some versions,however, the source of the power 418 may be provided from the separatemonitoring device 900 and its internal power supply 930. The power insuch a case is preferably delivered to the sensor device body via thecontacts, as described above, and may be conveyed through the tether964.

In the case of a wireless version of the sensor device body, atransceiver 420 is provided. The transceiver may alternatively be atransmitter, without a separate ability to receive signals from themonitoring device. Though not shown, the transceiver or transmitterincludes an antenna.

Preferably, the sensor device body includes a memory 421, which may beused as a cache for data detected by the detector, for programminginstructions operable by the microcontroller, or other purposes. Thememory may also include identifying information such as a serial numberor the like, which can be transmitted to or read by the monitoringdevice which can then interpret and display the identifying informationto indicate which type of sensor device body is in use, and a particularsuch device which has been identified. The memory may further includestored information such as the tubing set's drip factor (gtt/mL), asensor configuration, or yet other information which can be conveyed toa monitoring unit.

The monitoring device may include display unit 402, such as an LCD orLED screen. Display unit 402 may be employed to provide information to auser, including the information described above with reference to FIG.4.

A processor 422 is provided within the monitoring device 900, along witha memory 424 containing stored programming instructions operable by theprocessor to cause the monitoring device to control the sensor devicebody, retrieve data from the sensor device body, read data from memoryin the sensor device body, analyze and store data detected by thesystem, and control the display 402.

Monitoring devices may include a user input interface, or I/O device423, which may be in the form of button inputs as described above, orwhich may alternatively be in the form of a touch screen or otherinterface. The monitoring devices may include an audio interface as partof the I/O subsystem, such as a speaker used to provide audio alerts andother audio information to a user.

A power supply 930 is provided, which may be in the form of batteries,an AC power supply, or others.

The monitoring device further includes a transceiver 425, which may beconfigured with an antenna to send and receive data to and from thesensor device body, or to and from a remote computer, either directly orindirectly through various communications channels as described above.

A further alternate embodiment of a device for monitoring fluid througha drip chamber is illustrated in FIG. 17. In this version, the deviceincludes a tubing set and sensor device body, illustrated with anexemplary upper receiving tube 963 having an upper end in the form of aspike for insertion into a fluid source such as fluid source 191 asillustrated in FIG. 1. In alternate embodiment, the sensor device body950 preferably includes an infrared emitting diode 951, or IRED, and aphotodiode 952, or PD (see FIG. 10), which are positioned about a tubingset 953 in such a way so that drops falling from the top to the bottomof the tubing set will at least partially obscure or refract the beam955 which extends along a line of sight from the PD to the IRED. Asnoted above, the IRED and PD may alternately be any other form of sensorconfigured to detect drips falling through the sensor device body.

Most preferably, the IRED and PD are attached to a housing 956 formingthe sensor device body, and surrounding the tubing set or at leastextending along diametrically opposite portions of the tubing set. Insome versions of this alternate embodiment, the sensor device body neednot have a separate housing, but rather can comprise the tubing setitself, with the various components mounted to the tubing set. Mostpreferably, the components are permanently affixed to the drip set, suchas by gluing, molding, sonic welding, or using other such methods.

The alternate embodiment of FIG. 17, in some implementations, is capableof serving as a stand-alone device, without a separate or remotemonitoring unit or display. Accordingly, the sensor device body includes(either in the housing 956, or otherwise attached to the tubing set) amicrocontroller 416 to control the operation of at least the LED and PD,as well as the related components discussed with reference to FIG. 16.The processor controls the operation of LED and PD, and may perform theother services as described above.

The sensor device body also includes a source of power 418 (see FIG.16), which is not illustrated in FIG. 17 but which may be providedwithin the housing 956 or otherwise attached to the device. The powersupply may be in the form of an internal power supply, such as abattery, or may be a cord for AC power, a solar array strip, or have yetother forms.

Most preferably, this alternate version of the invention includes adisplay panel 941, which may be in the form of an LED or LCD display,for example, capable of displaying text messages, icons, or otherimages. In other versions, the display panel may be more simple, such asone or more LEDs or other indicators which may convey messages throughblinking, illumination, display of a particular color, or other formats.In the illustrated example, the display panel is provided on an exteriorsurface of the housing 956. The display panel is controlled by themicrocontroller, such as described above.

The version of FIG. 17 also preferably includes a user input device,which in the illustrated example is in the form of a button 942 providedon the housing 956 and in communication with the microcontroller 416.The button enables a user to toggle the device on or off, and to scrollthrough and select various possible commands to control the device. Someversions may include multiple buttons or switches attached to thedevice, or may incorporate a touch screen into the display panel 941 toserve as both a display and user input device.

The version of FIG. 17 is suitable, in some implementations, to serve asa disposable unit, with all of the necessary components built into andattached to the device. Such a version may optionally include atransceiver 420 (see FIG. 16) to enable it to communicate with a remotemonitoring unit. The device may further optionally include contacts or atether for direct connection with a monitoring unit, allowing a user toselectively use the device in a stand-alone manner, through physicalattachment to a monitoring device, or though wireless communication witha remote monitoring device.

Preferably, the sensor device body includes a memory 421 as describedabove, which may be used as a cache for data detected by the detector,for programming instructions operable by the microcontroller, or otherpurposes such as described above.

FIGS. 18-19 show additional views of a preferred monitoring device 800and a tubing set 953. The tubing set of FIGS. 18-19 does not include anintegrated sensor device body (such as sensor device body 950, describedabove). Instead, the tubing set is in the form of a separate dripchamber such as in FIGS. 1A and 3, to be used in a manner in which itmay be attached or mounted to a separate monitoring device such as thatof FIGS. 8A-C. The tubing set as illustrated in FIG. 18 includes acollar 975 shown in a partially exploded view. The tubing set (andcollar) are shown separated from the monitoring device in FIG. 18, withthe monitoring device also being shown alone in FIG. 19.

As with the monitoring device of FIGS. 8A-C, the monitoring device inFIGS. 18-19 includes an emitter or source 810 such as an infraredemitting diode, or IRED. An opposing detector 811 is visible in FIG. 19,positioned in opposition along the inner surface of the trench 864 asdescribed above with reference to FIGS. 8A-C. When the tubing set ismounted in the trench, the source and detector are positioned about thetubing set 953 in such a way so that drops falling from the top to thebottom of the tubing set will at least partially obscure or refract thebeam which extends along a line of sight from the source or emitter tothe detector.

The monitoring device 800 may include display unit 802, user inputinterface 806, and user audio interface 808, in the same manner asdescribed above.

The tubing set is illustrated with an exemplary upper receiving tube 963having an upper end in the form of a spike for insertion into a fluidsource such as fluid source 191 as illustrated in FIG. 1.

In one version, the collar 975 includes an upper opening 977 to allowthe spike 963 and an upper portion of the tubing set to pass through theopening as the collar surrounds the upper portion of the tubing set. Thecollar also includes a peripheral radially-extending flange 976, in themanner of the fins 960, 961 described above. Preferably, the flange 976is in the form of an annular flange which surrounds the collar andencircles the tubing set when attached to the tubing set. The collar maybe permanently attached to the tubing set, or in other versions may beremovably attachable.

The monitoring device includes a tubing set mount in the form of anattachment location preferably configured as a pair of mating channelssuch as channels 911, 912 described above and illustrated in FIG. 14.The flange is configured to be received within the mating channels ofthe monitoring device, thereby ensuring a snug fit of the housing to themonitor, including the alignment of the tubing set with respect to theemitter and detector. Thus, most preferably the tubing set (or collar)includes structural features that allow it to mount to the monitoringdevice, and further in which the IRED and PD are mounted on themonitoring device so that have a line of sight through the drip tube andare not subject to movement or faulty attachment by a user because theyare fixedly mounted in a proper location, diametrically opposite oneanother. As described above, the tubing set may further be secured inplace either with a mechanical latch, magnets, other mechanicalfeatures.

In the version particularly illustrated in FIGS. 18 and 19, the channels823, 825 of the monitoring device 800 are positioned at the top of thedevice, formed in an opposing pair of brackets 822, 824 which extendtoward one another, and in a direction toward the trench 864 in eachcase. The flange 976 is configured to be snugly received within thechannels 823, 825 in order to firmly hold the collar 975 and tubing set953 in place within the trench 864. Most preferably, the interior shapeof the channels within the brackets is in the form of a mating arccorresponding to the shape of the annular flange, such that the annularflange will be snugly and frictionally held within the channels, andfurther in which the annular flange can rotate while being held withinthe channels while holding the tubing set and drip tube in the sameposition with respect to its central axis.

While the preferred embodiment of the invention has been illustrated anddescribed, as noted above, many changes can be made without departingfrom the spirit and scope of the invention. Accordingly, the scope ofthe invention is not limited by the disclosure of the preferredembodiment. Instead, the invention should be determined entirely byreference to the claims that follow.

The invention claimed is:
 1. A monitoring device for monitoring fluidpassing through a drip tube of a tubing set, comprising: an emittermounted on the monitoring device; a detector mounted on the monitoringdevice; the emitter being positioned to emit electromagnetic radiationtoward the detector; the detector being positioned relative to theemitter receive to receive the electromagnetic radiation from theemitter and to generate a detector signal in response to electromagneticradiation received from the emitter; the emitter and detector beingpositionable about the tubing set, whereby the electromagnetic radiationpasses centrally through the drip tube from the emitter to the detector;a processor in communication with the detector; a memory having storedprogramming instructions operable by the processor to detect a fluiddrop passing through the drip tube based on the detector signal, andfurther to determine a first flow rate for the fluid based on a firstperiod, and a second flow rate for the fluid based on a second period,the first period being longer than the second period, and to communicateat least one of the first flow rate or the second flow rate to adisplay.
 2. The monitoring device of claim 1, wherein the monitoringdevice further comprises an alarm coupled to the processor, the storedprogramming instructions being operable by the processor to trigger thealarm when the first flow rate is greater than or less than a selectedflow rate by a threshold amount.
 3. The monitoring device of claim 2,wherein the threshold amount is plus or minus thirteen percent.
 4. Themonitoring device of claim 2, wherein the stored programminginstructions further cause the processor to communicate the first flowrate to the display when the alarm is enabled.
 5. The monitoring deviceof claim 4, wherein the stored programming instructions further causethe processor to communicate the second flow rate to the display whenthe alarm is disabled.
 6. The monitoring device of claim 5, wherein thestored programming instructions further cause the processor toautomatically enable the alarm a predetermined period of time after thealarm is triggered.
 7. The monitoring device of claim 6, wherein thepredetermined period of time is measured from a time after the secondflow rate is within the threshold amount.
 8. The monitoring device ofclaim 1, wherein the display is remote from the monitoring device. 9.The monitoring device of claim 1, wherein the first period and thesecond period are each based on a number of detected fluid drops, thefirst period being defined as a greater number of detected drops thanthe second period.
 10. A fluid monitoring system for monitoring fluidthrough a drip chamber, the system comprising: a source enabled to emitelectromagnetic radiation (EMR); a detector enabled to generate adetector signal; the source and detector being positioned about the dripchamber such that the source and the detector define a path across thedrip chamber between the source and the detector, wherein the detectoris positioned to generate the detector signal in response to the EMRemitted from the source; and a processor communicatively coupled to thesource and the detector and a memory accessible by the processor, thememory containing stored programming instructions, the processor beingoperable to execute the programming instructions to: detect a pluralityof fluid drops, each drop within the plurality of fluid drops beingdetected based on the passage of the drop across the path; and determinea first rolling average flow rate based on a first plurality of detectedfluid drops.
 11. The monitoring system of claim 10, further comprisingan alarm, and wherein the stored programming instructions are operableby the processor to cause the alarm to be triggered when the firstrolling average flow rate is outside a selected flow rate by a thresholdamount.
 12. The monitoring system of claim 11, wherein the storedprogramming instructions are operable by the processor to determine asecond rolling average flow rate for the fluid based on a secondplurality of detected fluid drops, the first plurality of detected fluiddrops being greater than the second plurality of detected fluid drops,and to communicate at least one of the first rolling average flow rateor the second rolling average flow rate to a display.
 13. The monitoringsystem of claim 12, wherein the stored programming instructions furthercause the processor to communicate the first rolling average flow rateto the display when the alarm is enabled.
 14. The monitoring system ofclaim 13, wherein the stored programming instructions further cause theprocessor to communicate the second rolling average flow rate to thedisplay when the alarm is disabled.
 15. The monitoring system of claim14, wherein the stored programming instructions further cause theprocessor to automatically enable the alarm a predetermined time afterthe alarm is triggered.
 16. The monitoring system of claim 15, wherein auser interface is provided on a remote device in communication with theprocessor.
 17. The monitoring system of claim 16, wherein the processordevice is configured for wireless communication with the remote device.